Good question, but not so sure it will give the desired answers. I heard that M-Sport had (or are about to) signed Juho Hänninen alongside Thierry Neuville. Hänninen will do Monte and Sweden, but probably only in an M2 car, as eventually only one driver will drive the #2 car permanently. My guessing is that #2 driver would be Neuville with Hänninen & Tänak going into the ERC but both doing WRC starts instead of ERC round 1.

Another example German champions Mark Wallenwein plans to do the whole ERC in a privateer Skoda but will still definitely be missing from Jänner Rallye.

Why? Jänner should be a fantastic event, but in an international calendar it is a very unfortunate event. The rally is to run 3rd-5th January, which means recce would have to start in the old year and go over the festive days! Add to that that some drivers may have contracts with their old teams until 31st December. How are teams going to manage this?

On the other hand, Jänner is a big favourite with direct neighbours Czech Republik. I.e. Vaclav Pech has entered the rally in his Mini SPC.

I would predict from all this, that a lot of people may do Jänner who are not doing the ERC, while a lot of people who intend to do the ERC will be missing in Jänner.